Sonic reserve alarm for air-breathing apparatus



April 5, 1966 E. H. REPLOGLE 3,

SONIC RESERVE ALARM FOR AIR-BREATHING APPARATUS Filed April 5, 1963 s Sheets-Sheet 1 INVENTOR.

April 5, 1966 E. H REPLOGLE 3,244,195

SONIC RESERVE ALARM FOR AIR-BREATHING APPARATUS Filed April 3, 1963 3 Sheets-Sheet 5 I NVENTOR.

ATTOZFMFYQ United States Patent 3,244,196 SONIC RESERVE ALARM FOR AER-BREATHING APPARATUS Edward H. Replogle, 7174 Transit Road, Buffalo, N.Y. Filed Apr. 3, 1963, Ser. No. 270,469 17 Claims. (Cl. 137-557) This application is a continuation-in-part of my copending application Serial No. 93,935 filed March 7, 1961, and bearing the same title as above, now abandoned.

This invention relates to improvements in air-breathing apparatus, and more particularly to alarm means for indicating sonically when the supply of air has been reduced to reserve pressure.

While the invention has application generally to all types of air-breathing apparatus and the like, it possesses particular advantages for self-contained underwater airbreathing apparatus. This latte-r type of air-breathing apparatus, as is well-known to those skilled in the art, includes one or more air tanks under a relatively high pressure, such tank being frequently charged to a pressure of about 2200 pounds per square inch (hereinafter referred to as p.s.i.) and also includes a first stage means for reducing the pressure of the air flowing from the aforesaid tank to a lower pressure such as 100 p.s.i. typically; and a second stage demand regulator which the user wears to supply him with air when under water. Underwater divers wearing such self-contained air-breathing apparatus often descend to considerable depths. To avoid injury to the diver, he should ascend to the surface at a controlled rate. If he is at a relatively great depth, this ascent takes a considerable time during which he must be supplied with air.

The primary object of the present invention is to provide air-breathing apparatus alarm means which are operative to indicate sonically when the supply of air has been reduced to a reserve or predetermined low pressure.

Another object is to provide air-breathing apparatus equipped with such alarm means which operates on the air in the breathing system.

A further object is to provide air-breathing apparatus equipped with such alarm means which does not lose or Waste air when the alarm means are being operated.

A further object is to provide air-breathing apparatus equipped with such alarm means which operate automatically so as not to require presetting by the user, thus being a safer appliance than manually controlled reserve valves heretofore used in air-breathing apparatus.

Still another object is to provide air-breathing apparatus equipped with such alarm means which cannot be turned off selectively and, therefore, cannot be used in a wrong position by mistake.

Another object is to provide such alarm means which are compact so that the same may be operatively incorporated in the conduit or line leading from the first stage pressure reducer means to the second stage pressure regulator means.

Other objects are to provide such alarm means which are simple in construction and hence relatively inexpensive, reliable in operation and not likely to get out of order or require repair.

Still other objects and advantages will be apparent from the following detailed description of a preferred embodiment of the present invention which is illustrated in the accompanying drawings wherein:

3,244,196 Patented Apr. 5, 1966 FIG. 1 is a fragmentary perspective view of self-contained air-breathing apparatus equipped with one form of sonic reserve alarm means embodying the present invention.

FIG. 2 is an enlarged fragmentary sectional view of the alarm means shown in FIG. 1 and also illustrating in section associated parts of the air-breathing apparatus, the alarm means being illustrated in the condition which it assumes when the air supply is above reserve or a predetermined low pressure.

FIG. 3 is a sectional view similar to FIG. 2 but showing essentially the alarm means only and illustrating the same in a condition when the reserve or predetermined low pressure of air supply is reached.

FIG. 4 is a sectional view similar to FIG. 3 and illustrating the alarm means in still another condition when the air supply has been reduced to reserve or a predetermined low pressure.

FIG. 5 is a transverse sectional view thereof taken on line 5-5 of FIG. 2.

FIG. 6 is a transverse sectional view thereof taken on line 66 of FIG. 2.

FIG. 7 is a transverse sectional view thereof taken on line 7-7 of FIG. 3.

FIG. 8 is a transverse sectional view thereof taken on line 8-8 of FIG. 4.

FIGS. 9 and 10 are fragmentary views similar to FIGS. 3 and 4, respectively, but showing a modified form of sonic reserve alarm.

FIGS. 1-8

The preferred embodiment of the present invention is illustrated in air-breathing apparatus of the self-contained type such as may be used for underwater diving. Referring to FIG. 1, the numeral 10 represents an air tank or cylinder in which air is maintained under pressure. This tank has a fitting 11 incorporating a shut-oif'valve (not shown) but the handle or knob for which is indicated at 12. The body of a first stage reducer indicated generally at 13 is shown as firmly clamped to the fitting 11 by the usual yoke 14. When so mounted, as is well-known, the inlet of the first stage reducer 13 communicates with the outlet of the aforesaid shut-off valve. Air discharged by the first stage reducer 13 flows through a conduit or hose 15 to a second stage demand regulator indicated generally at 16. The regulator 16 illustrated is of the type adapted to be carried in the mouth of the user although any other suitable type of demand regulator may be used, such as one incorporated in a full face mask.

What has been described so far is conventional. The inventive alarm means indicated generally at 18 are shown as arranged in the hose 15 and operatively interposed between the first and second stage means 13 and 16, respectively.

Referring to FIG. 2, the first stage reducer 13 is shown as including a body member 7 provided with a first or longitudinal through passage 8 and -a second or cross through passage 9 which intercepts the first passage 8 so as to establish communication therebetween. The inlet end of the body member 7, which is the upper end in FIG. 2, is shown as reduced as indicated at 17 and is provided with external threads to receive a flanged sleeve 19 which screws thereon. The spacing between the flange of the sleeve 19 and the central enlarged portion of the body member 7 provides an annular recess 20 which receives the annular end 21 of the yoke 14. By tighten- 3 ing the thumb screw 6 of the yoke 14 shown in FIG. 1, the inlet end 17 of the body member may be drawn firmly into sealed contact with the fitting 11 surrounding the outlet (not shown) for high pressure air leaving the tank The inlet portion of longitudinal passage 8 adjacent the reduced end 17 is shown as enlarged to house a filter 22 retained in position transverse of this passage by a snap ring 23. The filter 22 filters the air flowing from the tank 10 to the reducer body 7 in the direction of the arrow 24 shown in FIG. 2.

The portion of the longitudinal passage 8 on the lower side of the cross passage 9, as viewed in FIG. 2, is internally formed with an annular seat 25 which faces downstream or downwardly. A valve 26, preferably adjustably supported, is operatively associated with seat 25 so as to cooperate therewith in providing a restricted orifice. Air flowing through passage '8 and this restriction, provided by the spacing indicated at 28 between the opposing faces of seat 25 and valve 26, produces a pressure drop. The pressure of the air coming from the tank 1% which is often charged to a pressure of 2200 psi is throttled in flowing through restriction 28 to a much lower pressure such as about 100 p.s.i.

The valve 26 is shown as carried on the end of a valve spool 29 slidably arranged in the lower end portion of the longitudinal passage 8, as viewed in FIG. 2. The lower end of this spool 29 is enlarged to provide a piston head 30. Surrounding this piston head 30 and engaging the same is a cup-shaped cap or cylinder member 31. The lower end of the body member 7 is shown as reduced in transverse dimension as indicated at 32. This reduced end portion 32 is externally threaded to receive the internal threads formed on the open end of the cap 31. Referring to FIG. 2, this cap 31 is also provided with one or more holes 33 in its annular side wall above the piston head 30 so as to transmit ambient pressure from the exterior to the interior of the cap 31 and thereby place the upper face of the piston head 30 in communication with the ambient pressure.

The valve 26 which is preferably made of a hard plastic material such as nylon or Teflon is shown as being disc-shaped and held in the cupped end of a reduced inner end portion 34 formed on the valve spool 29. The reduced portion 34 is shown as provided with a transverse hole 35 which extends completely through this end portion. A longitudinal passage 36 is shown as internally formed within the spool 29, communicating at one end with the transverse passage 35 and at its other end opening to the lower end face 37 of the piston head 30, as viewed in FIG. 2, so as to communicate with a closed chamber 38 provided between the closed end of the cap 31 and the piston head 39.

A helical compression spring 39 is shown as surrounding the intermediate portion of the valve spool 29 with one end bearing against a shoulder 40 formed by counterboring the lower end portion of longitudinal passage 8, as viewed in FIG. 2, and at its other end bearing against the upper end face of the piston head '30.

It will be seen that ambient pressure acting against the upper end face of the piston head 36, together with the force exerted by the spring 39, counterbalance the force exerted by the reduced pressure on the downstream side of the seat 25 acting against the piston end face 37 and transmitted thereto from the portion of the passage 8 on the downstream side of the seat 25 via the passages 35 and 36.

Referring to FIG. 2, the right end portion of the cross passage 2 is shown as closed by a plug41 having a threaded engagement with body member '7. If desired, a pressure gauge may be mounted on the body member 7 in place of the plug 41. The opposite or left end portion of the cross passage 9 is shown as enlarged, as indicated at 42. The body member 7 is also shown as provided with a-passa'g'e 43 which places the enlarged portion -42 con- A stantly in communication with the portion of the longitudinal passage 8 on the downstream side of the seat 25.

The sonic reserve alarm means 18 are shown as comprising a tubular outer body member 44 which is reduced at one end and externally threaded to screw into the internally threaded enlarged portion 42 of the cross passage 9, as indicated at 45. Adjacent this reduced end, the outer body member 44 externally formed with out-ofround configuration, as indicated at 46 to permit the application of .a wrench (not shown) for tightening this body member 44 to the reducer body member 7. The other or left end of the outer body member 44, as viewed in FIG. 2, is shown as mounting a yoke member represented generally by the numeral 47.

This yoke member 47 is shown as having an end portion 48 preferably externally formed into an out-of-round configuration to permit the application of a wrench (not shown). The intermediate portion 49 of the yoke member 47 is shown as having external threads which screw into internal threads formed on the outer body member 44, as indicated at St). Inwardly of this intermediate portion 49, the yoke member is shown as having a stepped construction providing three axially facing annular shoulders 51, 52 and '53. The yoke member 46 is provided with a longitudinal through passage including an inner end portion 54 of reduced diameter, an intermediate portion 55 of larger diameter, and an outer end portion 56 of still larger diameter which is provided with internal threads. These threads 56 receive the externally threaded end 58 of a hollow fitting 59 suitably connected to one end of the hose 15. The yoke member 47 is shown as provided with a plurality of radial holes or passages 60 provided intermediate the shoulders 51 and 52.

Adverting to the outer body member 44, the same is shown as being tubular in form having .an enlarged interior for most of its length, as indicated at 61, and an end portion of reduced diameter, as indicated at 62, adjacent the body member 7 for the first stage reducer. The shoulder resulting from the different diametered bores 61 and 62 is formed to provide an annular seat 63 which faces downstream or to the left as viewed in FIG. 2.

Operatively associated with the seat 63 is a spring loaded valve member indicated generally at 64. This valve member 64 is operatively arranged within the tubular outer body member 44 and controls the flow of air through the composite bore 61, 62 of this body member and into the hose 15, and further is operated by pressure differential across the restriction 28 provided by the first stage reducer.

As shown, the valve member 64 comprises a piston head 65 formed at one end of a tubular portion 66. The end of this tubular portion 66 remote from the piston head 65 is shown as provided with an annular enlargement 68 to provide a valve head having a flat radial upstream side 69 adapted to seat against the annular seat 63. As shown in FIG. 5, the periphery of the valve head 68 is out-of-round, specifically hexagonal in shape, to provide radial clearances indicated at 7%} between the periphery of this value head and the opposing wall of the enlarged bore portion 61 of the outer body member 44. The valve member 64 is yieldingly urged toward its seat 63 by a helical compression spring 71, one end of which bears against the downstream side of the enlarged head 68 and the other end of which bears against the axially facing shoulder 51 formed on the yoke member 47. One or more holes or passages 72 are shown as formed in the wall of the tubular portion 66 of the valve member 64 for establishing communication between the exterior and interior of this tubular portion.

The main valve member 64 is also shown as formed with an annular seat 73 which faces downstream or to the left as viewed in FIG. 2. The seat 73 is located essentially at the downstream end of the tubular portion 66. A cylindrical tubular portion 74 of larger diameter than the tubular portion 66, surrounds the seat 73 and extends in a downstream direction, axially and concentrically with the first tubular portion 66. The downstream end face 75 of the tubular portion 74 is adapted to engage the opposing upstream facing annular shoulder 52 formed on the yoke member 47, as shown in FIG. 2. Engagement of the end face 75 with the shoulder 52 limits the travel of the valve member 64 in a leftward direction as viewed in FIG. 2, or, in other words, limits the lift of the valve head 68 off its seat 63.

A striker-valve member, indicated generally at 76, is slidably arranged in the tubular portion 74 of the main valve member 64. As shown, the striker-valve member 76 includes a body portion 78 which is spaced radially from the opposing circular wall of the tubular portion 74. At one end, this body 78 is enlarged into cupshaped form as indicated at 79. The cup-shaped head 79 is circular in cross section and its periphery is shown as having a radial clearance with the opposing circular inner surface of the tubular portion 74, as indicated at 80. This clearance 80 is best illustrated in FIG. 6. A valve head 81 is shown as carried by the cup-shaped enlargement 79 and is preferably made of relatively soft elastorner such as rubber or neoprene. The valve head 81 is shown as having a conical surface 82 adapted to engage the conical seat 73 formed on the main valve member 64. The tail or downstream end of the body member 78 of the striker-valve member 76 is shown as provided with a central axially extended stem 83 which is guidingly received in the hole 54 in the yoke member 47. A helical compression spring 84 for yieldingly urging the striker-valve member 76 toward its seat 73 is shown as surrounding the body portion 78. One end of this spring 84 bears against the upstream facing shoulder 52 on the yoke member 47 and the other end of this spring bears against the downstream facing shoulder formed by the enlargement 79.

A by-pass hole 85 is shown as provided in the main valve member 64. One end of this by-pass hole 85 communicates with the interior of the tubular portion 66 and the other end communicates with the annular space between the wall of the bore portion 61 and the tubular extension 74.

Operation Referring to FIG. 2, it will be seen that air entering the body member 7 of the first stage reducer 13 in the direction of the arrow 24 passes through the filter 22 thence through the inlet portion of the passage 8 into the intermediate portion of the cross passage 9, thence through the clearance 28 into the portion of longitudinal passage 8 downstream of seat 25, through the passage 43 into the bore 62. It will be noted that the piston head 65 of the main valve member 64 is slidably although sealingly arranged in the cylindrical intermediate portion of the cross passage 9. The end face of this piston head 65 which faces the plug 41 is subjected to the high air pressure on the upstream side of the restriction 28. However, inasmuch as the effective area on the lefthand side of this piston head 65 is subjected to air on the downstream side of the restriction 28 and hence at a lower pressure, there is a resultant or differential pressure effective upon the main valve member 64 urging the same to the left as viewed in FIG. 2. This leftward movement of the main valve member 64 by the aforesaid pressure differential is yieldingly opposed by the main valve spring 71 which urges the valve member 64 to the right, as viewed in FIG. 2, or toward the seat 63. Preferably, the spring rate of the spring 71 is such as to be effective to move the main valve member 64 into engagement with its seat 63 when the pressure differential effective upon the piston head 65 is about 200 p.s.i. In other words, the pressure in the air passage 8 upstream of the restriction 28 therein will be lowered to about 300 p.s.i.'when the compressed spring 71 expands to move the main valve member 64 into engagement with its seat 63, keeping in mind that the first stage reducer is adjusted to produce a pressure of about 100 p.s.i. downstream of the restriction 28.

Accordingly, FIG. 2 represents the open or unseated condition of the main valve member 64 when the pressure in the interconnected passages 8 and 9 upstream of the restriction 28 is above reserve or a predetermined low pressure, herein described typically as 300 p.s.i. In this open condition of the main valve member 64, the strikervalve member 76 will remain seated against its seat 73 because of the inability of the user breathing or demanding air through the hose to produce a large enough pressure differential across the striker-valve member 76 to unseat the same against the urging of its spring 84. The spring 84 is selected to have a spring rate such that a pressure differential of about p.s.i. across the strikervalve member 76 is required to lift this member off its seat 73.

With the main valve member 64 open or unseated as shown in FIG. 2, a flow path for air to the hose 15 is provided, such path beginning at the passage 43 including the annular space between the bore 62 and tubular portion 66, the space between the valve face 69 and seat 63, the clearances 70, the annular space between the bore 61 and tubular portion 74, and the radial holes leading from this last annular space into the interior of the yoke member 47 and the interior of the hollow hose fitting 58.

FIG. 3 represents the position of the main valve member 64 when the pressure in the interconnected chambers 8 and 9 upstream of the restriction 28 has dropped to a level low enough to enable the pressure differential acting upon the piston head no longer to hold the main valve member 64- away from its seat 63 against the urging of the main valve spring 71.

With the main valve member 64 seated, it is now assumed that the user draws a breath of air through the hose 15 so as to establish a pressure differential across the striker-valve member 76. Under this condition, the pressure within the tubular portion 66 of the main valve'mem ber 64 is higher than the pressure on the left or downstream side of the striker-valve member 76. When this pressure differential becomes about 20 p.s.i., the spring 84 can no longer maintain the striker-valve member 76 in engagement with its seat 73. Accordingly, the strikervalve member 76 unseats or lifts off its seat 73, moving to the left as viewed in FIG. 4 in a downstream direction. With the striker-valve member 76 unseated, as represented in FIG. 4, relatively high pressure air (about 100 p.s.i.) flows into the bore of the tubular portion 74 of the main valve member 64 and leaks past the periphery of the enlarged head portion 79 of the striker-valve member 76 through the clearance 80. The air thus flowing past the striker-valve member 76 flows out of the open end of the tubular portion 74 into the annular space between the yoke member 47 and the outer body member 44, thence through the radial hole 60 in this yoke member into the interior of the hose 15. Thus, a second flow path for air is established which is operative alternately with the first described flow path established when the main valve member 64 is open or off its seat 63.

It will be noted that when the valve head 81 of the striker-valve member 76 engages its seat 73, only an area A is exposed to the upstream pressure within the tubular portion 66 of the main valve member 64, as shown in FIG. 7. However, as soon as the striker-valve member 76 moves slidingly away from its seat 73, the full crosssectional area represented as B in FIG. 8 is exposed to this pressure. As a result, the striker-valve member 76 will be accelerated rapidly and move smartly toward the abutment surface 53 on the yoke member 46 and will forcefully engage or strike this surface thereby producing a noise which will be heard by the wearer of the airbreathing apparatus. Thus, a sonic alarm is produced which warns the user that he has reached the level of his reserve air and he should act accordingly.

If the clearance between the enlargedhead portion 79 of the striker-valve member 76 and the surrounding interior surface of the tubular extension 74 of the main valve member 64is sufficiently large so that when breathing at a normal rate, a sufiicient pressure drop or level cannot be maintained across the striker-valve member '76 to hold it open or away from its seat 73, this strikervalve assembly will reseat forthwith. Upon this occurring, the area exposed to the upstream pressure immediately returns from B area to A area so that the striker-valve member 76 will again be opened or unseated and driven against the abutment surface 53 to make another impact sound. Again assuming that an adequate pressure differential cannot be maintained across the striker-valve member 76 to hold it open, its spring 84" will reseat this member. This may occur several times as each breath is drawn by the user. Accordingly, a more frequently occurring impact sound is generated rather than just one impact sound with each breath. Providing a single or plural impact sound is a matter of preference.

From the foregoing, it will be seen that the inventive sonic reserve means provides an air-operated noise maker arranged to be inoperative when the main valve 64 is unseated to provide a first flow path, but which noise maker is operative when the main valve member 64 is seated blocking such flow path and thereby providing a second flow path past the noise maker. Thus, two flow paths for the air are provided which operate alternately. One path is around the main valve member 64- when the same is unseated and the striker-valve member 75 is seated. The second flow path is around the striker-valve member 76 when the same is unseated and the main valve member 64 is seated. It will be noted that the .air utilized to operate the noise maker is air which is breathed by the user and'isnot wasted r expended merely to operate the noise maker.

The by-pass hole 85 is provided so that the user can breathe his tank or supply of air down to zero and never experience a sudden shut-off of air. By air as usedin the specification and claims is meant any gaseous fluid suitable for breathing.

FIGS. 9 and Instead of providing a clearance around the striker valve member, one or more radial exhaust ports 99 may be provided in the tubular portion 74a of the member 76a adjacent the seat 73a downstream thereof as shown in FIGS. 9'and 10. There the valve head 79a of the member 76a is slightly larger in diameter than the head 76 shown in FIGS. 2-4 so that the clearance 80 is eliminated, thereby leaving the member 76a recip-rocably and substantially sealin-gly arranged within the. bore of the tubular portion. A free sliding fit is provided between the valve head 7% and the bore wall of the tubular portion 74a. Except for the elimination of the clearance 80 and the provision of the exhaust ports, the sonic alarm device shown in FIGS. 9 and 10 is similar to that shown in FIGS. 1-8 so that similar elements are designated with the suffix a after its reference numeral.

With the striker-valve member 76a seated as shown in FIG. 9, when the user inhales the air pressure downstream of this member or the seat 73a is lowered until a pressure differential across the exposed area.(A in FIG. 7) of this member is created sufficient to overcome the striker spring 84a. The member 76a runseats and instantly this pressure differential is applied to the full face area (B in FIG. 8). The higher pressure bearing against this full area drives the striker-valve member 76a to the left as viewed in FIGS. 9 and 10 and forcibly against the abutment surface (53in FIGS. 3 and 4) to make the noise of a strike.

As the member 76a moved leftward away from its seat 73a it uncovered the exhaust ports 9tl-allowing outwardly flow therethrough of air into the annular space between the tubular portion 74a and the surrounding housing 44a. Once there air flows, asv previously de- Cir scribed in connection with FIGS. 2-4, through the holes 60 into the interior of the yoke member 4'7 and the in te-rior of the hose fitting 58.

Such opening of the exhaust ports 9d-reduces the pressure differential across the member 76a enough to allow the spring 8411 to return this member rightward toward the seat 7301, thereby again covering these ports. As soon as the ports are covered a pressure differential of greater magnitude builds up across the member 76a causing it to make another strike.

This strike cycle repeats itself at resonant frequency which is determined by such factors as the mass of the striker-valve member 76a, the spring rate of the return spring 73a, and the length of the striker stroke. The net result is a continuous buzz during inhalation, instead of a single or multiple click as previously described in connection with FIGS. 18.

It is believed that the elastomeric valve element 81a which actually opposes the seat 73a does not reseat fully during its resonating movement. The periphery of the valve head 79a overtraveling across the ports during valve return probably traps a pocket of air in the annular space 91 to provide a dashpot effect, thus preventing forceful reseating which would cause excessive valve wear.

Further, variations and modifications of the embodiments shown and described herein may occur to those skilled in the art so that these. embodiments are illustrative and not' limitative of the invention, the scope of which is to be determined by the appended claims.

What is claimed is:

1. In air-breathing apparatus, the combination cornprisi-ng conduit means through which air flows, a movable member responsive to upstream air pressure, one position of said member providing a flow path for air, another position of said member blocking said How path, and air operated means in said conduit means operative for making noise when said member is in said another position and inoperative when said member is in said one position.

2; In air-breathing apparatus, the combination comprising conduit means through which air flows unidirectionally toward a point of use, a movable member arranged in said conduit means and responsive to upstream air pressure, means providing a seat for said member and facing downstream, spring means urging said member toward said seat, said member being unseated at all times when said pressure is above a predete mined level to provide a first flow path for air toward said point but being seated at all times when said pressure is below said level to block said first flow path, and means arranged to provide a second flow path for air toward said point and operative alternately with said first flow path and including an air operated noise maker, said second flow path never being provided by the last mentionedmeans when said pressure is above said level.

3; In air-breathing apparatus, the combination comprising conduit means through which air flows unidirectionally toward a point of use, a movable member arranged in said conduit means and responsive to upstream air pressure, means providing a seat for said member and facing downstream, spring means urging said member toward said seat, said member being unseated at all times when said pressure is above a predetermined level to provide a first flow path for air toward said point but being seated at all times when said pressure is below said level-to block said first flow path, and means arranged to provide a second flow path for air toward said point and operative alternately with said first flow path and including an air operated noise making movable striker, a seat on said member for said striker and facing downstream and spring means urging said striker toward its seat, said second flow path never being provided by the last mentioned means when said pressure is above said level;

4. In air-breathing apparatus, the combination comprising conduit means through which air flows, a movable member arranged in said conduit means and responsive to upstream air pressure, means providing a seat for said member and facing downstream, said member when unseated providing a first flow path for air but when engaging said seat blocking said first flow path, means arranged to provide a second flow path for air and operative alternately with said first flow path and including an air operated noise maker and means arranged to provide a third flow path by-passing said member when seated.

5. In air-breathing apparatus, the combination comprising means providing a flow passage for air, restriction means in said passage means to produce a pressure drop, a movable member having two effective sides one of which is subjected at all times to pressure upstream of said restriction means and the other of which is subjected at all times to pressure downstream of said restriction means, means providing a seat for said member and facing downstream, spring means urging said member toward said seat and opposing the eifect of upstream pressure on said member, said member when unseated providing a first flow path for air but when engaging said seat blocking said first flow path, and means arranged to provide a second flow path for air and operative alternately with said first flow path and including an air operated noise maker.

6. In air-breathing apparatus, the combination comprising means providing a flow passage for air, restriction means in said passage means to produce a pressure drop, a movable member having two eifective sides one of which is subjected at all times to pressure upstream of said restriction means and the other of which is subjected at all times pressure downstream of said restric tion means, means providing a seat for said member and facing downstream, spring means urging said member toward said seat and opposing the effect of upstream pressure on said member, said member when unseated providing a first flow path for air but when engaging said seat blocking said first flow path, and means arranged to provide a second flow path for air and operative alternately with said first flow path and including an air operated noise making movable striker, a seat on said member for said striker and facing downstream and spring means urging said striker toward its seat.

7. In air-breathing apparatus, the combination comprising means providing a flow passage for air, restriction means in said passage means to produce a pressure drop, a movable member including a piston portion having opposite sides communicating severally with said passage means on opposite sides of said restriction means, means providing a seat for said member and facing downstream, said member also including a valve portion arranged downstream of and adapted to engage said seat and a tubular portion, pressure upstream of said restriction means tending to unseat said member, spring means surrounding said tubular portion and urging'said member toward said seat and opposing the effect of upstream pressure on said member, said member when unseated providing a first flow path for air but when engaging said seat blocking said first flow path, a second seat on said member and facing downstream, means providing an abutment surface opposing and spaced downstream from said second seat, a striker arranged within said tubular portion and reciprocable between said second seat and said surface, and spring means arranged within said tubular portion and urging said striker toward said second seat, said striker when unseated providing a second flow path for air and operative alter nate-ly with said first flow path.

8. In air-breathing apparatus, the combination comprising means providing a flow passage for air, restriction means in said passage means to produce a pressure drop, a. movable member including a tubular portion closed at one end to provide a piston portion and an enlarged valve portion intermediate its ends, said piston portion being arranged so that its opposite sides communicate with said passage means on opposite sides of said restriction means, said tubular portion having at least one opening in its wall intermediate said piston valve portions, means providing a seat for said valve portion and arranged intermediate said piston and valve portions, pressure upstream of said restriction means tending to unseat said member, spring means surrounding said tubular portion and urging said valve portion toward said seat and opposing the effect of upstream pressure on said member, said member when unseated providing a first flow path for air between said valve portion and its said seat but which path is blocked when said member is seated, an internal seat on said tubular portion and facing downstream, means providing an abutment surface opposing and spaced downstream from said internal seat, a striker arranged within said tubular portion and reciprocable between said internal seat and surface, and spring means arranged within said tubular portion and urging said striker toward said internal seat, said striker when unseated providing a second flow path for air and operative alternately with said first flow path.

9. In air-breathing apparatus, the combination comprising means providing an air flow passage having a restriction therein, means providing in said passage a first seat facing downstream, a main valve member having a portion opposing and engageable with said first seat and having oppositely facing portions severally exposed to the pressures on opposite sides of said restriction whereby said main valve member is operated by pressure diiferential across said restricttion, first spring means urging said main valve member toward engagement with said first seat, said main valve member including a tubular portion having a conduit establishing communication between the upstream and downstream sides of said main valve member, means providing a second seat surrounding said conduit and facing downstream, means providing in said passage an abut ment surface opposing and spaced downstream from said second seat, and a striker-valve member reciprocably arranged in said tubular portion within said conduit downstream of said second seat and having a part operatively interposed and of shorter length than the distance between said surface and second seat and adapted for alternate engagement therewith and operated by pressure differenial across said striker-valve member, sec ond spring means urging said striker-valve member toward engagement with said second seat, a clearance existing between said striker-valve member and the wall of said tubular portion, said clearance communicating with that portion of said conduit upstream of said second seat when said striker-valve member is unseated but such communication is blocked when said striker-valve member is seated.

10. In air-breathing apparatus, the combination comprising means providing an air flow passage having a restriction therein, means providing in said passage a first seat facing downstream, a main valve member having a portion opposing and engageable with said first seat and having oppositely facing portions severally exposed to the pressures on opposite sides of said restriction whereby said main valve member is operated by pressure differential across said restriction, first spring means urging said main valve member toward engagement with said first seat, said main valve member including a tubular portion having a conduit establishing communication between the upstream and downstream sides of said main valve member, means providing a second seat surrounding said conduit and facing downstream, means providing in said passage an abutment surface opposing and spaced downstream from said second seat, a striker-valve member reciprocably and substantially sealingly arranged in said tubular portion within said conduit downstream of said second seat and having a part operatively interposed and of shorter length than the distance between said-surface and second seat and adapted for alternate engagement therewith and operated by pressure differential across said striker-valve member, second spring means urging said striker-valve member toward engagement with said second seat, and exhaust port means in the wall of said tubular portion extending between the interior and exterior thereof and communicating with said interior adjacent said second seat, said port means being closed by said striker-valve member when close to a seated condition on said second seat but being uncovered when said striker-valve member moves away from said second seat.

11. In air-breathing apparatus, the combination comprising means providing an air flow passage having a restriction therein, means providing in said passage a first seat facing downstream, a main valve member having a portion opposing and engageable with said first seat and having oppositely facing portions severally exposed to the pressures on opposite sides of said restriction whereby said main valve member is operated by pressure differential across said restriction, first spring means urging said main valve member toward engagement with said first seat, said main valve member including a tubular portion having a conduit establishing communication between the upstream and downstream sides of said main valve member, means providing a second seat surrounding said conduit and facing downstream, means providing in said passage an abutment surface opposing and spaced downstream from said second seat, a strikervalve member reciprocably and substantially sealingly arranged in said tubular portion within said conduit downstream of said second seat and having a part operatively interposed and of shorter length than the distance between said surface and second seat and adapted for alternate engagement therewith and operated by pressure differential across said striker-valve member, second spring means urging said striker-valve member toward engagement with said second seat, exhaust port means in the wall of said tubular portion extending between the interior and exterior thereof and communicating with said interior adjacent said second seat, said port means being closed by said striker-valve member when close to a seated condition-on said second seat but being uncovered when said striker-valve member moves away from said second seat, and means defining a pocket between said main valve member and striker-valve member as the latter reseats and which pocket is out of communication withsaid port means and is reduced in volume by the approach of said striker-valve member toward said second seat whereby air trapped within said pocket escapes through the gradually reducing clearance between said second seat and striker-valve member to produce a dashpot effect preventing forceful reseating.

12. In air-breathing apparatus having conduit means supplying air to second stage pressure regulator means, the combination therewith of sonic reserve alarm means disposed upstream of said conduit means and operated solely by air flowing through said conduit means toward said second stage means and without loss of air and operatively arranged to indicate sonically when the supply of air has been reduced to reserve pressure.

13. In air-breathing apparatus, the combination comprising first means providing a conduit through which air can flow and having a restriction therein to provide a pressure drop, second means arranged within said conduit to control the flow of air through a first flow path, third means arranged within said conduit to make noise and to control the flow of air through a second fiow path, and fourth means to render said second means effective to provide said first flow path in response to air pressure upstream of said restriction above a predetermined level, said third means being operative to provide said second flow path when the upstream pressure is below said level.

14. In air-breathing apparatus, the combination comprising means providing a main air flow passage having a restriction therein, a seat surrounding said main passage and arranged downstream of said restriction and facing downstream, a valve member arranged in said main passage and urged to move away from said seat by pressure upstream of said restriction, spring means urging said valve member to move toward said seat, said valve member having an auxiliary passage communicating with said main passage downstream of said restriction, a second seat surrounding said auxiliary passage and facing downstream, means providing an abutment surface opposing and spaced downstream from said second seat, a striker-valve member reciprocable between said second seat and surface, and spring means urging said strikervalve member toward its seat.

15. In air-breathing apparatus, the combination comprising means providing a main air flow passage having a restriction therein, a seat surrounding said main passage and arranged downstream of said restriction and facing downstream, a valve member arranged in said main passage and urged to move away from said seat by pressure upstream of said restriction, spring means urging said valve member to move toward said seat, said valve member having an auxiliary passage communicating with said main passage downstream of said restriction, a second seat surrounding said auxiliary passage and facing downstream, means providing an abutment surface opposing and spaced downstream from said second seat, a striker-valve member reciprocable between said second seat and surface, and spring means urging said striker-valve member toward its seat, said striker-valve member when seated exposing a smaller area to upstream pressure than when unseated.

16. In air-breathing apparatus, the combination comprising means providing a main air flow passage having a restriction therein, a first seat surrounding said main passage and arranged downstream of said restriction and facing downstream, a main valve member arranged in said main passage and urged to move away from said first seat by pressure upstream of said restriction, first spring means urging said main valve member to move toward said first seat, said main valve member having an auxiliary passage communicating with said main passage downstream of said restriction, a second seat surrounding said auxiliary passage and facing downstream, means providing in said auxiliary passage an abutment surface opposing and spaced from said second seat, a strikervalve member movably interposed between said surface and second seat and adapted for alternate engagement therewith, and second spring means urging said strikervalve member toward said second seat, said striker-valve member when seated exposing a smaller area to upstream pressure that when unseated.

17. In air-breathing apparatus, the combination comprising means providing a main air fiow passage having a restriction therein, a first seat surrounding said main passage and arranged downstream of said restriction and facing downstream, a main valve member arranged in said main passage and urged to move away from said first seat by pressure upstream of said restriction, first spring means urging said main valve member to move toward said first seat, said main valve member having an auxiliary passage communicating with said main passage downstream of said restriction, a second seat surrounding said auxiliary passage and facing downstream, means providing in said auxiliary passage an abutment surface opposing and spaced from said second seat, a striker-valve member movably interposed between said surface and second seat and adapted for alternate engagement therewith, and second spring means urging said striker-valve member toward said second seat, said striker-valve member when seated exposing a smaller area to upstream pressure than when unseated, said main valve member 13 14 having a by-pass opening therein constantly maintaining 2,632,465 3/ 1953 Schweisthal 137-557 communication with said auxiliary passage upstream of 2,653,626 9/1953 Finlayson 137--599.2 said second valve seat. 2,704,035 3/1955 Bader 137-5'1-2.2 2,828,739 4/1958 Kimes 1-37-63 References Cited by the Examiner 5 3,050,076 8/ 1962 .F 137 1 1() UNITED STATES PATENTS 3,056,378 10/1962 Simmonds u--. 116-70 2,200,310 5/1940 Thayer 137557 2,359,008 9/1944 Smith 137 63 M. CARY NELSON, Pnmary Examzner.

2 53 435 1 1 51 FOX 137 MARTIN P. SOHWADRON, Examiner. 

1. IN AIR-BREATHING APPARATUS, THE COMBINATION COMPRISING CONDUIT MEANS THROUGH WHICH AIR FLOWS, A MOVABLE MEMBER RESPONSIVE TO UPSTREAM AIR PRESSURE, ONE POSITION OF SAID MEMBER PROVIDING A FLOW PATH FOR AIR, ANOTHER POSITION OF SAID MEMBER BLOCKING SAID FLOW PATH, AND AIR OPERATED MEANS IN SAID CONDUIT MEANS OPERATIVE FOR MAKING NOISE WHEN SAID MEMBER IS IN SAID ANOTHER POSITION AND INOPERATIVE WHEN SAID MEMBER IS IN SAID ONE POSITION. 